Presently, two types of semiconductor processing systems are employed for fabricating semiconductor work pieces. The first type of system is a batch processing system; while the second type of system which is commonly used processes single semiconductor work pieces. In batch processing systems, semiconductor work pieces are typically oriented in either a horizontal or vertical orientation, and are thereafter processed at the same time.
Although single piece semiconductor processing systems have many advantages including producing uniform semiconductor products, they also have numerous shortcomings including low throughput; high overhead operating costs; and problems achieving uniform heating of the semiconductor work pieces that are being processed. These long recognized problems associated with single piece processing devices have yet to be overcome.
Attempts have been made to address the problems associated with the prior art batch processing systems. For example, in U.S. Pat. No. 5,855,681, a batch processing system is described, and which includes multiple processing chambers. Each of the processing chambers includes multiple processing stations. In this prior art device, the processing chambers can process multiple semiconductor work pieces at one time.
While these and other devices have worked with some degree of success, there are shortcomings that have detracted from their usefulness. For example, one of the biggest problems associated with batch processing systems lies principally with insuring uniformity during the processing of the respective semiconductor work pieces. In this regard, when batch processing a plurality of semiconductor work pieces, the multiple semiconductor work pieces are placed in the same chamber. Consequently, differences in heat and gas flow in the processing chamber may cause non-uniform processing of the several semiconductor work pieces. To overcome the problems associated with non-uniform processing, several solutions have been proposed. For example, and referring now to FIG. 1, a processing apparatus for semiconductor work pieces 10 is illustrated and wherein a silicon substrate to be processed 11 is placed on a carbon pedestal 12. Positioned below and in spaced relation relative to the carbon pedestal there is a second, heating pedestal 13. Located within the heating pedestal there is a high frequency heating coil 14 which is operable to impart heat energy to the silicon substrate 11. During processing, the carbon pedestal 12 can rotate around a central shaft together with the carbon pedestal support 15. This arrangement has been utilized to try to insure uniform temperature processing.
Referring now to FIG. 2, another prior art semiconductor work piece processing apparatus 20 is disclosed and which is more particularly discussed in published U.S. Patent Application 2005/0011459. The semiconductor processing apparatus 20 includes a rotatable semiconductor work piece carrier 21 which is positioned within a processing chamber 22. A semiconductor work piece 23 is placed on the semiconductor work piece carrier 21. The semiconductor work piece carrier 21 rotates around a shaft 24. Further, a heating pedestal 25 is provided which is stationary, and located in a position which is closely adjacent thereto. A small passageway 26 is defined between the semiconductor work piece carrier 21, and the adjacent reaction chamber 22. In the present prior art device, the semiconductor work piece carrier is rotated while gas is simultaneously delivered to the reaction chamber and flows horizontally, outwardly along the passageway 26. This arrangement attempts to provide uniform film growth on the semiconductor work piece 23 during processing.
While many of the difficulties associated with prior art batch processing devices utilized heretofore can be remedied by means of the prior art devices shown in FIGS. 1 and 2, these same assemblies also create other problems. In both prior art devices, multiple semiconductor work pieces are placed on the same semiconductor work piece carrier. Further, these same semiconductor work piece carriers are heated by a stationary heating pedestal. Uniform heating of the semiconductor work pieces is affected by the rotation of the semiconductor work piece carrier apparatus relative to the stationary heating pedestal. The difficulty associated with this particular type of approach is that the separation of the heating apparatus from the semiconductor work piece carrier adds a degree of complexity to the overall processing system. Still further, achieving a uniform space or gap between the semiconductor work piece carrier and the underlying heating pedestal becomes difficult thereby making the control of the processing temperature an increasing problem. In addition to the foregoing difficulties, the prior art devices all employ semiconductor work piece carriers which are driven or rotate thereabout a common shaft. This is not an ideal solution for semiconductor processing devices which have multiple processing stations within one processing chamber.
Therefore, a semiconductor processing apparatus which avoids the shortcomings attendant with the prior art practices and methodology utilized heretofore is the subject matter of the present application.